Although Mr Riedijk is on a terrorism watch list, his Dutch citizenship has not been revoked.

However, BBC foreign correspondent Anna Holligan said Ms Begum would struggle to get her underage marriage recognised in the Netherlands, and any application for a residence permit would be jeopardised by the fact that she too was suspected of terrorist crimes.

Their newborn son though, might be entitled to Dutch citizenship through his father, she added.

Recently, the Dutch justice department has warned of the threat posed by jihadist women returning from abroad.

It said even women and children, who were not trained and did not take part in hostilities, could pose a “long-term potential threat” because of exposure to IS ideology.

Mr Riedijk was born and raised in Dutch suburbia but abandoned his life in 2014 to join IS.

He was one of 300 Dutch men and women who travelled to Syria and Iraq, our correspondent said.

Of those, some 135 Dutch nationals with “jihadist intentions” are still there, anti-terrorism officials say.

It is not known how many want to come back and it is not clear if they can. Last week the Netherlands removed the citizenship of Mr Riedijk’s fellow Dutch jihadist Outhmane B.